1. Field of the Technology
The present technology relates to an electrophotographic lenticular lens sheet manufacturing apparatus.
2. Description of the Related Art
An electrophotographic image forming apparatus is capable of forming a high-quality image with favorable reproducibility and operability at low cost. This is why the electrophotographic image forming apparatus has been widely used in a copier, a printer, a facsimile machine, a multifunction machine having two or more of these functions just stated, and the like machine.
Recording mediums used in an image forming apparatus of an electrophotographic system include lenticular lens sheets having a lens layer of a concavo-convex shape formed on one side in a thickness direction of a transparent substrate, in addition to recording sheets in which both sides in a thickness direction have a smooth surface, such as a paper sheet, a plastic sheet and an OHP sheet.
When an image is formed on a lenticular lens sheet by an image forming apparatus, a three-dimensional image and an image in which a two-dimensional image, but plural images are switched by changing a viewing angle, are expressed.
Japanese Unexamined Patent Publication JP-A 2008-26477 discloses a method for forming an image on a lenticular lens sheet. According to the technology disclosed in JP-A 2008-26477, image formation with a toner is conducted using a recording medium comprising a transparent substrate, a thermoplastic resin layer for forming a lens layer on one side of the transparent substrate and a thermoplastic resin layer for the image formation with a toner formed on other side thereof, and pressure is then applied under heating to the thermoplastic resin layer for forming a lens layer to shape the thermoplastic resin layer into a concavo-convex shape, thereby forming a lens layer.
That is, the technology disclosed in JP-A 2008-26477 is that a lens layer having a concavo-convex shape is formed using a preliminarily prepared recording medium having formed thereon a thermoplastic resin layer for forming a lens layer. Therefore, the technology uses a plurality of apparatuses, that is, an apparatus for forming a thermoplastic resin layer on a transparent substrate and an apparatus for forming a lens layer by shaping the thermoplastic resin layer into a concavo-convex shape. As a result, it does not say that the technology is convenient as an apparatus constitution for manufacturing a lenticular lens sheet.
To overcome the above problem, an apparatus shown in FIG. 7 is considered as a lenticular lens sheet manufacturing apparatus that can manufacture a lenticular lens sheet in a single apparatus. FIG. 7 is a view showing a constitution of a lenticular lens sheet manufacturing apparatus 600.
The lenticular lens sheet manufacturing apparatus 600 shown in FIG. 7 is an apparatus for manufacturing a lenticular lens sheet comprising a transparent substrate and a lens layer having a concavo-convex shape, formed on one side in a thickness direction of the transparent substrate, in an electrophotographic system. The lenticular lens sheet manufacturing apparatus 600 comprises a transparent toner image forming section 601, a transfer section 602, a sheet feed section 603 and a lens forming section 605. The transparent toner image forming section 601 comprises a photoreceptor drum 611, a charging section 612, an exposure section 613, a developing section 614, a developer supply section 615, a drum cleaner 616 and a charge removing section 617.
In the lenticular lens sheet manufacturing apparatus 600, an electrostatic latent image is formed on the photoreceptor drum 611 by the charging section 612 and the exposure section 613, the electrostatic latent image is developed by the developing section 614 using a transparent toner to form a transparent toner image, the transparent toner is supplied to the developing section 614 by the developer supply section 615, residual transparent toner on the photoreceptor drum 611 is removed by the drum cleaner 616, and charge removal of the photoreceptor drum 611 is performed by the charge removing section 617.
The transparent substrate is fed to the transfer section 602 by the sheet feed section 603, a transparent toner image formed on the photoreceptor drum 611 is transferred to the one side of the transparent substrate by the transfer section 602, the transparent substrate having the transparent toner image transferred thereto is pressurized under heating to fix the transparent toner image to the transparent substrate, and at the same time, the transparent toner image is shaped into a concavo-convex shape, thereby forming a lens layer, by the lens forming section 605.
According to the lenticular lens sheet manufacturing apparatus 600 as shown in FIG. 7, a lenticular lens sheet comprising a transparent substrate having formed on the one side thereof a lens layer having a concavo-convex shape can be manufactured by a single apparatus, but it does not say that the lenticular lens sheet manufactured has good quality. The reason for this is as follows.
In the lenticular lens sheet manufacturing apparatus 600, the transparent substrate having a transparent toner image transferred thereto is pressurized under heating to fix the transparent toner image to the transparent substrate, and additionally the transparent toner image is shaped into a concavo-convex shape, thereby forming a lens layer, by the lens forming section 605. It is difficult to set the heating conditions in the lens forming section 605 such that a high quality lenticular lens sheet can be manufactured.
To form a lens layer, a surface of a member such as a roller of the lens forming section 605 for use in lens formation is processed into a shape according to a lens shape. In order that a transparent toner image is melted in a nip of the lens forming section 605 and the transparent toner image is shaped into a lens shape so as to fit to the shape of the roller member surface, the roller member is required to have a so-called hard roller structure that the surface does not have a rubber layer. For this reason, it is difficult to obtain a wide width of a nip.
To fix the transparent toner image transferred to the one side of the transparent substrate, the transparent toner image is required to heat at high temperature. In order to melt and fix the transparent toner image completely by a roller member of a hard roller structure having a narrow nip width in the lens forming section 605, the surface temperature of the roller member is required to be very high temperature. The transparent toner image thus heated at high temperature decreases its viscosity. As a result, hot offset resistance decreases, thereby surface smoothness of the lens layer is decreased.
To suppress occurrence of hot offset, heating temperature of the time of heating the transparent toner image should be decreased. However, in this case, adhesive strength of the lens layer to the transparent substrate is decreased, and for example, the lens layer separates when merely lightly touching with a finger.
That is, in the lenticular lens sheet manufacturing apparatus 600, the transparent substrate having a transparent toner image transferred thereto is pressurized under heating to fix the transparent toner image to the transparent substrate, and additionally the transparent image toner is shaped into a concavo-convex shape, thereby forming a lens layer, by the lens forming section 605. Therefore, the degree of freedom of temperature setting at the formation of the lens layer is low, and it is difficult to set the heating conditions in the lens forming section 605 such that a high quality lenticular lens sheet can be manufactured.